Use ALPN in rustls

[jsha]

No description provided.

[bagder]

The travis build is unhappy:

vtls/rustls.c: In function ‘cr_init_backend’:
vtls/rustls.c:337:3: error: implicit declaration of function ‘rustls_client_config_builder_set_protocols’; did you mean ‘rustls_server_config_builder_set_protocols’? [-Wimplicit-function-declaration]
   rustls_client_config_builder_set_protocols(config_builder, alpn, 2);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   rustls_server_config_builder_set_protocols
vtls/rustls.c:337:3: error: nested extern declaration of ‘rustls_client_config_builder_set_protocols’ [-Werror=nested-externs]
vtls/rustls.c: In function ‘cr_set_negotiated_alpn’:
vtls/rustls.c:393:3: error: implicit declaration of function ‘rustls_client_session_get_alpn_protocol’; did you mean ‘rustls_client_session_read_tls’? [-Wimplicit-function-declaration]
   rustls_client_session_get_alpn_protocol(session, &protocol, &len);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   rustls_client_session_read_tls
vtls/rustls.c:393:3: error: nested extern declaration of ‘rustls_client_session_get_alpn_protocol’ [-Werror=nested-externs]
cc1: all warnings being treated as errors

[bagder]

Ah, I guess that is because of the waiting PRs mentioned here already...

[jsha]

Oops, sorry about that. The crustls PR was merged, but I needed to tag a new release (0.5.0). I've done that now and updated .travis.yml and docs/RUSTLS.md to match.

[bagder]

Thanks!